How to create derived metrics in Foglight

Hi. This is Robert Statsinger. I'm a Foglight solution architect. Today I'd like to show you how to create a simple derived metric in Foglight. In Foglight, a derived metric is a metric based on calculations of the data from other metrics. You can take existing data from your agents and perform arbitrary mathematical calculations to create new metrics that are mathematical functions such as trends, averages, baselines, and other kinds of aggregations of existing data. When you do this, the new metric will be treated just as any other metric inside Foglight. You can graph it in dashboards and use it in rules and alarms.
Today we'll create a simple derived metrics that exists as a ratio of the number of forks to interrupts in the Linux operating system. So I will go to the Create Derived Metric area. And I will give a name for my derived metric called forksToInterruptsRatio.
And then I will add a calculation. And I will scope the derived metric against a data type, which is the kernel metrics data. And I will validate that scope. And then I will add an expression that says return (#forks#/#interrupts#). I'll validate the expression, and then I will click the Add button.
Now, the next thing I'll do is I'll give this derived metric a unit name. I could really choose from any unit name I want, but in this case, I'll choose percent. And I'll say Add. Now I have a new metric called forksToInterruptsRatio that lives on the same data object as the originating data that I used in the calculation. So now I can actually go into that data and pull out the new metric.
So I'll open up the data tree here and find the topology type on which I scoped the derived metric. And here it is. And here is my new metric, which is a percentage ratio. I'll pull it out, and put it on this little dashboard, and say Finish. And I'll edit the page layout a little bit just to make things a little more clear. And then over time, this percentage will populate with the value of the new metric.
For more information on Foglight's derived metrics capability, you can consult our documentation. And for more information on Foglight in general, please visit software.dell.com/foglight.